On 18/08/2013 20:30, Richard Smith wrote: > On 18/08/13 20:24, Graeme Wall wrote: > >> 1900s plural is the decade, just as 1920s plural is the decade. > > You may use that convention, but a lot of people do use 1900s to mean > the century, so the ambiguity is still there. I have never heard of 1900s to refer to the whole century. It is usually called the twentieth century or 20th C. 1900s refers to the first decade of the 20th century.